PARIS --- The French response to the January massacre at Charlie Hebdo and the subsequent killing of four Jews in a kosher supermarket has been exemplary. President Francois Hollande and his combative prime minister, Manuel Valls, have made clear what is at stake --- the Republic itself --- and they have drawn a line: This shall not pass. Hollande has discovered his inner statesman; Valls, an immigrant himself, has been impassioned about the values of openness, diversity and freedom of expression that must define France. The inner Voltaire slumbering in the French soul has stirred. Goaded, a majority of French men and women will defend to the death the right of others to disagree with them. They will not succumb to bigotry or the savagery of the movement calling itself the Islamic State.

But of course, whatever your love for France, if you are a Jewish couple dropping your children off every day at a school guarded by police and soldiers with machine guns you may begin to ask yourself if those children have a future in the country. (There are reports of gendarmes with weight problems, so prolific are the cakes and cookies handed to them by grateful Jewish moms.) You may wonder if Israel or the Upper West Side might not be a better option. Prominent Jews, like prominent caricaturists, are looking over their shoulders. Some are under police protection. This, to state the obvious, is a necessary but not ideal state of affairs.

Roger Cukierman, the president of the Representative Council of Jewish Institutions in France, told me that the number of Jews leaving had risen sharply, from about 2,000 in 2012 to 7,000 last year. This year, he said, there will be more than 10,000 who depart. This is not an exodus; it is a significant trend. “The decision to leave is a respectable choice, but it is a bad sign for France,” Cukierman said. “We cannot criticize it. We have too many memories of people who tried to leave too late from France, and other countries.”

Vichy is always in the back of the French mind, the great betrayal of the nation’s Jewish citizens that took decades, and Jacques Chirac, to be acknowledged in full. If the emancipation of Europe’s Jews was galvanized by the French Revolution, the limits of that emancipation were delineated at the Vel d’Hiv in 1942, when almost 13,000 Jews were rounded up in a Paris cycling stadium, among them 4,051 children. Most went to their deaths. The distance from the Republic’s ideals to that shame is a measure of how inextricable to France’s self-esteem and very nature the fate of its 500,000 Jews has become. If the country of Leon Blum and Raymond Aron has no place for its Jews, tribal horror is upon us.

We are not there yet. Then, anti-Semitism had infiltrated the establishment. Today Hollande and Valls are resolute. French Jews are not cowed. Anti-Semites proliferate but have no effective leadership. Still, the air is tinged with unease.

Bernard-Henri Levy, the writer and intellectual, described the new French anti-Semitism as a fusion of strands from the far left to the far right, a hodgepodge of extreme anti-Zionists who do not hesitate to equate Israel with Nazism, Holocaust deniers who believe history has been twisted to serve Jewish ends, and people convinced the suffering of Algerians, Palestinians and other Muslims has been overshadowed through Jewish manipulation, wealth and power.

Dieudonne M’bala M’bala, the self-styled comedian and popularizer of an inverted Nazi salute known as the “quenelle,” has successfully trafficked in these resentments.

There is no question that poisonous Middle Eastern politics have been imported into France through its large Jewish and Muslim populations in a way that has no equivalent elsewhere in Europe. Dalil Boubakeur, the moderate president of the French Council of the Muslim Faith, described to me a mood of “suspicion and mistrust” between Muslims and Jews, and growing fundamentalism among French Muslims who feel humiliated, forced to pray in improvised premises or even in the streets because of a lack of mosques. “I am behind the curve,” he said. “I would have liked a tranquil Islam.” He said he was lunching with the French chief rabbi this week but if he ever went to Israel he would be “killed as soon as I got back to France.”

With the far-right National Front party rising, France has become the central battle ground of Europe’s postwar values. If it loses, none of humanity will be spared.

I believe the fight will be long and the French Republic will prevail. Dominique Moisi, a political scientist and son of an Auschwitz survivor, told me he would never leave France because of threats to Jews, but nor would he live in a France governed by Marine Le Pen.

Principle and indignation are rising in France as a sense of the dangers grows. This is the chief harvest of January --- defiance.